Merge 4.4.113 into android-4.4

Changes in 4.4.113
	gcov: disable for COMPILE_TEST
	x86/cpu/AMD: Make LFENCE a serializing instruction
	x86/cpu/AMD: Use LFENCE_RDTSC in preference to MFENCE_RDTSC
	x86/mm/32: Move setup_clear_cpu_cap(X86_FEATURE_PCID) earlier
	x86/asm: Use register variable to get stack pointer value
	x86/kbuild: enable modversions for symbols exported from asm
	x86/asm: Make asm/alternative.h safe from assembly
	EXPORT_SYMBOL() for asm
	kconfig.h: use __is_defined() to check if MODULE is defined
	x86/retpoline: Add initial retpoline support
	x86/spectre: Add boot time option to select Spectre v2 mitigation
	x86/retpoline/crypto: Convert crypto assembler indirect jumps
	x86/retpoline/entry: Convert entry assembler indirect jumps
	x86/retpoline/ftrace: Convert ftrace assembler indirect jumps
	x86/retpoline/hyperv: Convert assembler indirect jumps
	x86/retpoline/xen: Convert Xen hypercall indirect jumps
	x86/retpoline/checksum32: Convert assembler indirect jumps
	x86/retpoline/irq32: Convert assembler indirect jumps
	x86/retpoline: Fill return stack buffer on vmexit
	x86/retpoline: Remove compile time warning
	scsi: sg: disable SET_FORCE_LOW_DMA
	futex: Prevent overflow by strengthen input validation
	ALSA: pcm: Remove yet superfluous WARN_ON()
	ALSA: hda - Apply headphone noise quirk for another Dell XPS 13 variant
	ALSA: hda - Apply the existing quirk to iMac 14,1
	af_key: fix buffer overread in verify_address_len()
	af_key: fix buffer overread in parse_exthdrs()
	scsi: hpsa: fix volume offline state
	sched/deadline: Zero out positive runtime after throttling constrained tasks
	x86/retpoline: Add LFENCE to the retpoline/RSB filling RSB macros
	module: Add retpoline tag to VERMAGIC
	pipe: avoid round_pipe_size() nr_pages overflow on 32-bit
	x86/apic/vector: Fix off by one in error path
	Input: 88pm860x-ts - fix child-node lookup
	Input: twl6040-vibra - fix DT node memory management
	Input: twl6040-vibra - fix child-node lookup
	Input: twl4030-vibra - fix sibling-node lookup
	tracing: Fix converting enum's from the map in trace_event_eval_update()
	phy: work around 'phys' references to usb-nop-xceiv devices
	ARM: dts: kirkwood: fix pin-muxing of MPP7 on OpenBlocks A7
	can: peak: fix potential bug in packet fragmentation
	libata: apply MAX_SEC_1024 to all LITEON EP1 series devices
	dm btree: fix serious bug in btree_split_beneath()
	dm thin metadata: THIN_MAX_CONCURRENT_LOCKS should be 6
	arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls
	x86/cpu, x86/pti: Do not enable PTI on AMD processors
	kbuild: modversions for EXPORT_SYMBOL() for asm
	x86/mce: Make machine check speculation protected
	retpoline: Introduce start/end markers of indirect thunk
	kprobes/x86: Blacklist indirect thunk functions for kprobes
	kprobes/x86: Disable optimizing on the function jumps to indirect thunk
	x86/pti: Document fix wrong index
	x86/retpoline: Optimize inline assembler for vmexit_fill_RSB
	MIPS: AR7: ensure the port type's FCR value is used
	Linux 4.4.113

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

1 files changed, 157 insertions, 9 deletions

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index cd46f9039119..49d25ddf0e9f 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -10,6 +10,9 @@
 #include <linux/init.h>
 #include <linux/utsname.h>
 #include <linux/cpu.h>
+
+#include <asm/nospec-branch.h>
+#include <asm/cmdline.h>
 #include <asm/bugs.h>
 #include <asm/processor.h>
 #include <asm/processor-flags.h>
@@ -20,16 +23,10 @@
 #include <asm/pgtable.h>
 #include <asm/cacheflush.h>
 
+static void __init spectre_v2_select_mitigation(void);
+
 void __init check_bugs(void)
 {
-#ifdef CONFIG_X86_32
-	/*
-	 * Regardless of whether PCID is enumerated, the SDM says
-	 * that it can't be enabled in 32-bit mode.
-	 */
-	setup_clear_cpu_cap(X86_FEATURE_PCID);
-#endif
-
 	identify_boot_cpu();
 
 	if (!IS_ENABLED(CONFIG_SMP)) {
@@ -37,6 +34,9 @@ void __init check_bugs(void)
 		print_cpu_info(&boot_cpu_data);
 	}
 
+	/* Select the proper spectre mitigation before patching alternatives */
+	spectre_v2_select_mitigation();
+
 #ifdef CONFIG_X86_32
 	/*
 	 * Check whether we are able to run this kernel safely on SMP.
@@ -69,6 +69,153 @@ void __init check_bugs(void)
 #endif
 }
 
+/* The kernel command line selection */
+enum spectre_v2_mitigation_cmd {
+	SPECTRE_V2_CMD_NONE,
+	SPECTRE_V2_CMD_AUTO,
+	SPECTRE_V2_CMD_FORCE,
+	SPECTRE_V2_CMD_RETPOLINE,
+	SPECTRE_V2_CMD_RETPOLINE_GENERIC,
+	SPECTRE_V2_CMD_RETPOLINE_AMD,
+};
+
+static const char *spectre_v2_strings[] = {
+	[SPECTRE_V2_NONE]			= "Vulnerable",
+	[SPECTRE_V2_RETPOLINE_MINIMAL]		= "Vulnerable: Minimal generic ASM retpoline",
+	[SPECTRE_V2_RETPOLINE_MINIMAL_AMD]	= "Vulnerable: Minimal AMD ASM retpoline",
+	[SPECTRE_V2_RETPOLINE_GENERIC]		= "Mitigation: Full generic retpoline",
+	[SPECTRE_V2_RETPOLINE_AMD]		= "Mitigation: Full AMD retpoline",
+};
+
+#undef pr_fmt
+#define pr_fmt(fmt)     "Spectre V2 mitigation: " fmt
+
+static enum spectre_v2_mitigation spectre_v2_enabled = SPECTRE_V2_NONE;
+
+static void __init spec2_print_if_insecure(const char *reason)
+{
+	if (boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
+		pr_info("%s\n", reason);
+}
+
+static void __init spec2_print_if_secure(const char *reason)
+{
+	if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
+		pr_info("%s\n", reason);
+}
+
+static inline bool retp_compiler(void)
+{
+	return __is_defined(RETPOLINE);
+}
+
+static inline bool match_option(const char *arg, int arglen, const char *opt)
+{
+	int len = strlen(opt);
+
+	return len == arglen && !strncmp(arg, opt, len);
+}
+
+static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
+{
+	char arg[20];
+	int ret;
+
+	ret = cmdline_find_option(boot_command_line, "spectre_v2", arg,
+				  sizeof(arg));
+	if (ret > 0)  {
+		if (match_option(arg, ret, "off")) {
+			goto disable;
+		} else if (match_option(arg, ret, "on")) {
+			spec2_print_if_secure("force enabled on command line.");
+			return SPECTRE_V2_CMD_FORCE;
+		} else if (match_option(arg, ret, "retpoline")) {
+			spec2_print_if_insecure("retpoline selected on command line.");
+			return SPECTRE_V2_CMD_RETPOLINE;
+		} else if (match_option(arg, ret, "retpoline,amd")) {
+			if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) {
+				pr_err("retpoline,amd selected but CPU is not AMD. Switching to AUTO select\n");
+				return SPECTRE_V2_CMD_AUTO;
+			}
+			spec2_print_if_insecure("AMD retpoline selected on command line.");
+			return SPECTRE_V2_CMD_RETPOLINE_AMD;
+		} else if (match_option(arg, ret, "retpoline,generic")) {
+			spec2_print_if_insecure("generic retpoline selected on command line.");
+			return SPECTRE_V2_CMD_RETPOLINE_GENERIC;
+		} else if (match_option(arg, ret, "auto")) {
+			return SPECTRE_V2_CMD_AUTO;
+		}
+	}
+
+	if (!cmdline_find_option_bool(boot_command_line, "nospectre_v2"))
+		return SPECTRE_V2_CMD_AUTO;
+disable:
+	spec2_print_if_insecure("disabled on command line.");
+	return SPECTRE_V2_CMD_NONE;
+}
+
+static void __init spectre_v2_select_mitigation(void)
+{
+	enum spectre_v2_mitigation_cmd cmd = spectre_v2_parse_cmdline();
+	enum spectre_v2_mitigation mode = SPECTRE_V2_NONE;
+
+	/*
+	 * If the CPU is not affected and the command line mode is NONE or AUTO
+	 * then nothing to do.
+	 */
+	if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2) &&
+	    (cmd == SPECTRE_V2_CMD_NONE || cmd == SPECTRE_V2_CMD_AUTO))
+		return;
+
+	switch (cmd) {
+	case SPECTRE_V2_CMD_NONE:
+		return;
+
+	case SPECTRE_V2_CMD_FORCE:
+		/* FALLTRHU */
+	case SPECTRE_V2_CMD_AUTO:
+		goto retpoline_auto;
+
+	case SPECTRE_V2_CMD_RETPOLINE_AMD:
+		if (IS_ENABLED(CONFIG_RETPOLINE))
+			goto retpoline_amd;
+		break;
+	case SPECTRE_V2_CMD_RETPOLINE_GENERIC:
+		if (IS_ENABLED(CONFIG_RETPOLINE))
+			goto retpoline_generic;
+		break;
+	case SPECTRE_V2_CMD_RETPOLINE:
+		if (IS_ENABLED(CONFIG_RETPOLINE))
+			goto retpoline_auto;
+		break;
+	}
+	pr_err("kernel not compiled with retpoline; no mitigation available!");
+	return;
+
+retpoline_auto:
+	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {
+	retpoline_amd:
+		if (!boot_cpu_has(X86_FEATURE_LFENCE_RDTSC)) {
+			pr_err("LFENCE not serializing. Switching to generic retpoline\n");
+			goto retpoline_generic;
+		}
+		mode = retp_compiler() ? SPECTRE_V2_RETPOLINE_AMD :
+					 SPECTRE_V2_RETPOLINE_MINIMAL_AMD;
+		setup_force_cpu_cap(X86_FEATURE_RETPOLINE_AMD);
+		setup_force_cpu_cap(X86_FEATURE_RETPOLINE);
+	} else {
+	retpoline_generic:
+		mode = retp_compiler() ? SPECTRE_V2_RETPOLINE_GENERIC :
+					 SPECTRE_V2_RETPOLINE_MINIMAL;
+		setup_force_cpu_cap(X86_FEATURE_RETPOLINE);
+	}
+
+	spectre_v2_enabled = mode;
+	pr_info("%s\n", spectre_v2_strings[mode]);
+}
+
+#undef pr_fmt
+
 #ifdef CONFIG_SYSFS
 ssize_t cpu_show_meltdown(struct device *dev,
 			  struct device_attribute *attr, char *buf)
@@ -93,6 +240,7 @@ ssize_t cpu_show_spectre_v2(struct device *dev,
 {
 	if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2))
 		return sprintf(buf, "Not affected\n");
-	return sprintf(buf, "Vulnerable\n");
+
+	return sprintf(buf, "%s\n", spectre_v2_strings[spectre_v2_enabled]);
 }
 #endif